D2D Synchronization Signal Resource Allocation in Asynchronous Networks
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Solution Overview
Problem
In device-to-device (D2D) communication within asynchronous networks, there is a need to specify how remaining physical resource blocks (PRBs) in the first sub-frame of the discovery-resource pool should be used to avoid wasting spectrum resources and minimize interference, especially when multiple discovery-resource pools are allocated in a frequency-division multiplexing manner.
Innovation Solution
The solution involves defining rules for resource allocation in the first sub-frame of a discovery-resource pool, where the central six PRBs are used for D2D synchronization signals, and the remaining PRBs can be either left unused, allocated for normal wide-area network transmissions, or used for discovery-signal transmission with appropriate power control to reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the remaining PRBs in the first sub-frame are allocated for discovery-signal transmission, then spectrum efficiency is improved, but interference on D2D synchronization signals increases
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different PRBs within the first sub-frame. The central six PRBs are designated exclusively for D2D synchronization signals with high transmission power, while the remaining PRBs can be allocated for discovery-signal transmission with controlled power levels. This local differentiation allows spectrum utilization in non-critical regions while protecting the synchronization signal quality in critical regions.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting transmission power levels for different signal types in different PRBs. The eNB configures power control parameters that allow discovery signals to be transmitted in remaining PRBs at reduced power compared to synchronization signals in central PRBs, thereby improving spectrum efficiency while maintaining acceptable interference levels.
2Object-generated harmful factors
If the remaining PRBs are used for normal wide-area network transmissions, then interference on D2D synchronization signals is minimized, but spectrum resources are wasted
Solution Approach 1:
The patent applies universality by enabling the remaining PRBs to serve multiple functions depending on network conditions and configuration. These PRBs can be dynamically allocated for discovery-signal transmission when D2D discovery activity is high, or for normal wide-area network transmissions when interference concerns dominate. This multi-functional capability allows the system to adaptively utilize spectrum resources without permanently sacrificing synchronization signal quality.
3Productivity
If multiple discovery-resource pools are allocated in frequency-division multiplexing manner, then D2D discovery capacity is improved, but resource allocation complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the available spectrum into multiple discovery-resource pools that are frequency-division multiplexed. Each pool is assigned specific PRBs in the first sub-frame, with clear boundaries and allocation rules. The eNB configures each pool with specific parameters including PRB ranges, power control settings, and transmission timing, allowing multiple pools to coexist with manageable complexity through structured resource partitioning.
Data Source
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AI summary
Technology to improve resource allocation for inter-cell device-to-device (D2D) discovery and timing synchronization between user equipments (UEs) connected to asynchronous network deployments is disclosed. Also, transmission rules are provided for networks wherein discovery-resource pools are allocated in a frequency-division- multiplexing (FDM) manner. In the first sub-frame of a transmission-resource pool, there may be overlap between resources that are allocated for a discovery-resource pool and resources that are allocated for D2D synchronization signals (D2DSSs). Non-overlapping PRBs in the discovery-resource pool can be allocated for WAN transmission or D2D- discovery transmission. In scenarios where discovery-resource pools are allocated using FDM, a measurement such as reference signal received power (RSRP) or path loss can be made for a UE. The measurement can be compared to a threshold value to determine whether the UE will transmit a D2DSS.